Draft-controlling device for furnaces



March 4 1924. 1,485,613

G. E. HULL.

DRAFT CONTROLLING DEVICE FOR FURNACES Filed Sent. 8, 1923 "'0 0 1 INVENTOR.

z 0 ATTORA Patents Mar. t, was. 7

GEORGE E. HULL, or PITCAIRN, PENNSYLVANIA.

DRAFT-CONTROLLING DEVICE FOR, FURNACES. i

Application filed. September 8, 1923. Serial No. 661,617.

To all whom it may concern: 7

Be it known that I, GEORGE E. HULL, a citizen of the United States, residing at Pitcairn, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Draft-Controlling Devices for Furnaces, of which the following is a specification, reference being had to the accompanying drawings. V

This invention relates to improvements in draft controlling devices for furnacesand the like and has for an important object thereof the provision of a device of this character which is simple in its construction and operation and which will prevent overheating'of the furnace to which it is applied.

A further object of the invention is to provide a device of this'character which is fluid operated and which employs as a motive fluid water, which is easily replaceable when exhausted. v

A still further object of the invention is to provide a device of this character which may be applied to the furnace witha minimum amount of change in the structure thereof and which may be very cheaply and readily produced.

These and other objects I attain by the construction shown in the accompanying drawings wherein for the purpose of illustration is shown a preferred embodiment of my invention and wherein Figure 1 is a side elevation of a control device constructed in accordance with my invention applied to a furnace;

Figure 2 is a sectional view showing the location of the offset within the furnace flue pipe; and

Figure 3 is a detail sectional view taken through the control element.

Referring now more particularly to the drawings, the numeral 10 indicates a substantially vertically disposed conduit having at its upper end a valve 11. and a filling funnel 12, passage of the fluid from the funnel to the conduit being controlled by the valve The conduit 10 is provided intermediate its ends with an offset section 13 which is adapted to be arranged in the flue pipe 14 of a furnace 15 between the furnace and the flue damper.

Above the oflset section 13 one end of a coil 16 communicates with the conduit 10,

the lower end of this coil communicating with the conduit below the offset. This coil is arranged exteriorly of the flue pipe and at a point where it is not affected materially by the heat of the furnace. In the coil is disposed a valve 17for a purpose presently to appear. Beneath the point of connection of the lower end of the coil with the conduit 10 a second conduit 18 communicates with the conduit 10, this conduit having a vertically arranged portion provided at its upper end with a bowl 19 in which is arranged a flexible diaphragm 20. The cover 21 of the bowl forms aguide for the stem 22 of a plunger having its lower end resting upon the diaphragm, as indicated at 23. This cover also forms a mounting for a support 24 upon which is pivoted a lever 25, the ends of which are provided with flexible elements 26- one of which may be connected with the ash pit draft door 27 of the furnace 15 and the other of which is connected with the damper 28 of the flue pipe. The upper end of the plunger 22 engages one end of the lever 25 and this end of the lever has preferably mounted thereon an adjustable weight 29. The lower end of the conduit 10 is preferably provided with a drain valve 30. i

In the use of the device the system is filled through the funnel 12 until water flows from the valve 17 which is arranged at a point on the coil such that when the coil and system are filled to this level with water the fluid when expanded by heat will expand sufliciently to elevate the flexible diaphragm 20. After filling, the valve 11 is closed and in event of heat in the flue pipe rising to a point where the heat applied to the fluid within the offset portion 13 of the conduit 10 is not counteracted by the condensing action of the coil 16, the fluid by its expansion lifts the diaphragm 20 thereby lifting with it the corresponding end of the lever 25. This results in the closing of the ash pit door and of the damper 28 of the flue pipe checking the drafts ofthe furnace. As the heat decreases the fluid will contract with the result that these dampers will be again opened permitting the furnace to resume normal operation. It will be noted that the structure provided is extremely simple and one which may be readily applied to the furnace without any material changes in the construction thereof. It will further be noted that certain changes and modifications of the structure are possible Without in any manner departing from the spirit of my invention and I accordingly do not limit myself to such specific structure as hereinbefore set forth except as hereinafter claimed.

I claim 1. In a damper regulator for furnaces, a pivoted lever arm controlling the draft and damper doors of the furnace and normally disposed in one position and means for shifting said lever arm including a circulation system having a coil positioned to be subjected to the flames passing through the flue of the furnace, a second coil in parallel to the first named coil and subjected to the action of air, a diaphragm, and a connection between said coils and said diaphragm whereby expansion of fluid contained within the coils elevates said diaphragm to shift said lever, the connection between the coils and diaphragm comprising a bowl within which the diaphragm is located and to the upper end of which the diaphragm is sealed, a connection between the coils and the lower end of the bowl, and means resting upon the diaphragm and connected with said lever for shifting the lever.

2. In furnace control apparatus, a pivoted lever normally disposed in one position, a connection between opposite ends of the lever and the draft and damper doors of the furnace whereby when the lever is in said position the draft door is opened and the damper door is closed, and means for shifting said lever upon overheating of the furnace including a heating coil subjected to heat passing through the flue of the furnace, a condenser coil receiving heated fluid from the first named coil and in parallel with the first named coil, a diaphragm located beneath the lever, a push rod abutting the diaphragm and pivotally connected with the lever, a bowl in which the diaphragm is located, and a connection between the lower end of the bowl and said heating coil.

3. In a damper regulator for furnaces, a pivoted lever arm controlling the draft and damper doors of the furnace and normally disposed in one position and means for shifting said lever arm including a circulation system having a coil positioned to be subjected to the flames passing through the flue of the furnace, a second coil in parallel to the first named coil and subjected to the action of air, a diaphragm, and a connection between said coils and said diaphragm whereby expansion of fluid contained within the coils elevates said diaphragm to shift said lever.

In testimony whereof I hereunto affix my signature.

GEORGE E. HULL. 

